Our goals are to increase our knowledge of the composition of oviductal secretions and how they may affect the establishment and maintenance of pregnancy by characterizing molecular interactions between the unfertilized ovum, spermatozoa and fertilized ovum which may be mediated by oviductal proteins. The initial objective of this proposal is to characterize the proteins synthesized and secreted by the porcine oviduct under the influence of estrogen and progesterone; that is, proteins which contribute to the appropriate environment for establishment of pregnancy. This includes maintenance of the ovum, capacitation of spermatozoa, fertilization and early embryonic development. Two of our major aims will be to study regulation of synthesis and secretion of oviductal proteins by endogenous steroids during the estrous cycle and early pregnancy, and by exogenously administered steroids in ovariectomized animals. This will be accomplished using labelled precursors in explant cultures assuming secretory activities characteristic of the in vivo situation is maintained in a controlled in vitro setting. Radiolabelled proteins will be identified by fluorography after 2D-PAGE. The role of different functional segments (A,I,AIJ) in synthesis and secretion will also be assessed. Another aim will be to study ultrastructural changes mediated by ovarian steroids with light and electron microscopy in both intact and ovariectomized animals, and correlate changes with secretion of specific proteins. A major aim will be to purify the major oviductal secretory proteins, specifically those produced under estrogen dominance when ovum and sperm are present. Biochemical characterization will include determination of Mr, pI, carbohydrate content, and any enzyme activity. Using these purified proteins, polyclonal monospecific antiserum will be prepared for immunocytochemical studies to define the site of synthesis, granule formation and extracellular distribution. This will allow more precise studies of hormone control. Another aim will be to assess whether these proteins possess immunosuppressive or complement inhibitory activity, important for establishment and maintenance of pregnancy. This study will provide important data in a different animal model on: 1) ovarian steroid regulation of oviductal secretory proteins, 2) identification of estrogen-specific and progesterone-specific proteins, 3) biochemical characterization of these proteins, and 4) ovarian steroid-induced ultrastructural changes.